It is widely understood that children at highest risk for chronically aggressive, antisocial behavior are those who display high rates of aggression very early in development, making early childhood the most desirable period for prevention and early intervention efforts. Because antisocial outcomes are multiply determined, multicomponent interventions are necessary to adequately interrupt the trajectory of aggressive behavior patterns. The purpose of the present investigation is to implement and evaluate a multicomponent preventive intervention for children at risk for chronically aggressive behavior. The components include both classroom-based (teacher and student focused programs) and home-based interventions (home visits by paraprofessionals and parent groups offered at the Head Starts). To date, the effects of behavioral consultation with teachers on children's classroom behavior have been examined. Behavioral observation revealed no reliable differences between the intervention and control groups, with both groups showing significantly improved behavior over time. Follow-up analyses were conducted to discern the pattern of changes within groups. These tests showed a significant drop in total inappropriate behavior for the intervention group by January, and for the control group by March. Teacher report using standard preschool behavior rating scales showed that the intervention, but not the control group, improved over the period from October to February. The children in classrooms in which the interventions were implemented were rated by their teachers as showing significant reductions in total problem behavior, hostile-aggressive, hyperactive, and anxious-fearful behaviors.